Extraction of large valence-band energy offsets and comparison to theoretical values for strained-Si/strained-Ge type-II heterostructures on relaxed SiGe substrates
Author(s)
Teherani, James T.; Chern, Winston; Antoniadis, Dimitri A.; Hoyt, Judy L.; Ruiz, Liliana; Poweleit, Christian D.; Menendez, Jose; ... Show more Show less
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Metal-oxide-semiconductor capacitors were fabricated on type-II staggered gap strained-Si/strained-Ge heterostructures epitaxially grown on relaxed SiGe substrates of various Ge fractions. Quasistatic quantum-mechanical capacitance-voltage (CV) simulations were fit to experimental CV measurements to extract the band alignment of the strained layers. The valence-band offset of the strained-Si/strained-Ge heterostructure was found to be 770, 760, and 670 meV for 35, 42, and 52% Ge in the relaxed SiGe substrate, respectively. These values are approximately 100 meV larger than the usually recommended band offsets for modeling Si/Ge structures. It is shown that the larger valence-band offsets found here are consistent with an 800-meV average valence-band offset between Si and Ge, which also explains the type-II band alignment observed in strained-Si[subscript 1−x]Ge[subscript x] on unstrained-Si heterostructures.
Date issued
2012-05Department
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer ScienceJournal
Physical Review B
Publisher
American Physical Society
Citation
Teherani, James et al. “Extraction of Large Valence-band Energy Offsets and Comparison to Theoretical Values for strained-Si/strained-Ge type-II Heterostructures on Relaxed SiGe Substrates.” Physical Review B 85.20 (2012). ©2012 American Physical Society
Version: Final published version
ISSN
1098-0121
1550-235X